Caffeine for asthma

Background Caffeine has a variety of pharmacological effects; it is a weak bronchodilator and it also reduces respiratory muscle fatigue. It is chemically related to the drug theophylline which is used to treat asthma. It has been suggested that caffeine may reduce asthma symptoms and interest has been expressed in its potential role as an asthma treatment. A number of studies have explored the effects of caffeine in asthma, this is the first review to systematically examine and summarise the evidence. Objectives To assess the effects of caffeine on lung function and identify whether there is a need to control for caffeine consumption prior to either lung function or exhaled nitric oxide testing. Search strategy We searched the Cochrane Airways Group trials register and the reference lists of articles (August 2009). We also contacted study authors.Selection criteriaRandomised clinical trials of oral caffeine compared to placebo or coffee compared to decaffeinated coffee in adults with asthma. Data collection and analysis Trial selection, quality assessment and data extraction were done independently by two reviewers. Main results Seven trials involving a total of 75 people with mild to moderate asthma were included. The studies were all of cross-over design.Six trials involving 55 people showed that in comparison with placebo, caffeine, even at a 'low dose' (< 5 mg/kg body weight), appears to improve lung function for up to two hours after consumption. Forced expiratory volume in one minute showed a small improvement up to two hours after caffeine ingestion (SMD 0.72; 95% CI 0.25 to 1.20), which translates into a 5% mean difference in FEV1. However in two studies the mean differences in FEV1 were 12% and 18% after caffeine. Mid-expiratory flow rates also showed a small improvement with caffeine and this was sustained up to four hours.One trial involving 20 people examined the effect of drinking coffee versus a decaffeinated variety on the exhaled nitric oxide levels in patients with asthma and concluded that there was no significant effect on this outcome. Authors' conclusions Caffeine appears to improve airways function modestly, for up to four hours, in people with asthma. People may need to avoid caffeine for at least four hours prior to lung function testing, as caffeine ingestion could cause misinterpretation of the results. Drinking caffeinated coffee before taking exhaled nitric oxide measurements does not appear to affect the results of the test, but more studies are needed to confirm this

Nonpharmacologic Strategies to Manage Exercise-Induced Bronchoconstriction

Pharmacological management of exercise induced bronchoconstriction (EIB) is the mainstay of preventative therapy. However, there are some non-pharmacological interventions that may assist the management of EIB. In this review we will discuss these non-pharmacological interventions and how they may be applied to patients and athletes with EIB

Recent consumption of a large meal does not affect measurements of lung function

Background and objective: It is currently recommended that patients avoid large meals prior to their lung function tests. The aim of this study is to determine whether this recommendation is necessary in clinical practice. Methods: A randomized controlled cross-over trial was conducted. Subjects performed lung function tests (spirometry, measurement of lung volumes and gas transfer) prior to, directly following and 2 h after consuming a large breakfast. On the control arm, subjects performed the same lung function tests while fasting for the duration of the morning. The study subjects comprised 12 healthy subjects, 10 COPD patients and 10 patients with interstitial lung disease. Results: There were no significant differences between measurements on the meal and control days for FEV1, FVC, TLC or DLCO. There were no significant changes with time in any of these parameters over the course of either the meal or control morning. Conclusions: Common measures of lung function are not affected by the prior consumption of a large meal and it is unnecessary to advise patients to avoid a large meal prior to lung function measurement